In a cellular communication system, a base station provides services to a plurality of terminals linked therewith using a proportional fair scheduling algorithm. The term ‘service’ means an action that the base station takes in order to transmit radio data packets to each terminal. If the base station provides services to each terminal using a related-art proportional fair scheduling algorithm, a transfer rate is estimated mainly in a single antenna system. If a linkage between the base station and each terminal has a Rayleigh fading channel and a burst transfer rate is a linear function of the signal to noise ratio (SNR), the long-term transfer rate is calculated using the following equation 1:
                    R        =                              1            N                    ⁢                      G            ⁡                          (              N              )                                ⁢                      E            ⁢                                                  [            r            ]                                              [                  Equation          ⁢                                          ⁢          1                ]            
wherein R is a long-term transfer rate, N is the number of terminals linked with a base station simultaneously,
      G    ⁢                  ⁢          (      N      )        =      1    +          1      2        +    …    +          1      N      is a multi-user gain, and E[r] is a mean transfer rate between a base station and a specific terminal. However, [Equation 1] is applied to only the single antenna system and cannot be extended to a multiple antenna system. Also, if the burst transfer rate is not a liner function of the SNR in a real single antenna system, many errors may occur in estimating a long-term transfer rate and thus it is difficult to calculate an exact value.